Commit 40011850 authored Jan 03, 2024 by Fedor Pchelkin Committed by Sasha Levin Mar 15, 2024

btrfs: ref-verify: free ref cache before clearing mount opt



[ Upstream commit f03e274a8b29d1d1c1bbd7f764766cb5ca537ab7 ]

As clearing REF_VERIFY mount option indicates there were some errors in a
ref-verify process, a ref cache is not relevant anymore and should be
freed.

btrfs_free_ref_cache() requires REF_VERIFY option being set so call
it just before clearing the mount option.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Reported-by:  <syzbot+be14ed7728594dc8bd42@syzkaller.appspotmail.com>
Fixes: fd708b81 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 5.4+
Closes: https://lore.kernel.org/lkml/000000000000e5a65c05ee832054@google.com/


Reported-by:  <syzbot+c563a3c79927971f950f@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/lkml/0000000000007fe09705fdc6086c@google.com/


Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent d623fd52

fs/btrfs/ref-verify.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -891,8 +891,10 @@ int btrfs_ref_tree_mod(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
		out_unlock:
		spin_unlock(&root->fs_info->ref_verify_lock);
		out:
		if (ret)
		if (ret) {
		btrfs_free_ref_cache(fs_info);
		btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
		}
		return ret;
		}

		@@ -1021,8 +1023,8 @@ int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
		}
		}
		if (ret) {
		btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
		btrfs_free_ref_cache(fs_info);
		btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
		}
		btrfs_free_path(path);
		return ret;